Degree Of Freedom Robot Research Articles

A study on the dynamics of a novel seven degrees of freedom spray-painting robot with a telescopic forearm

In this article, the dynamics of a seven degrees of freedom robot with a telescopic forearm for the spray-painting of large workpiece is investigated. A novel two-step inverse kinematic solving method that combines numerical and analytical approaches is proposed to solve the inverse kinematics of the seven degrees of freedom robot with two redundant degrees of freedom for spray-painting applications. Based on the kinematic model, the dynamic model is derived using the Newton–Euler method. For the dynamic parameter identification, the dynamic model is written in a linear form with respect to dynamic parameters. Considering the effect of the telescopic forearm on the dynamics of the robot, two novel performance indices concerning the inertial load and gravitational load in the joint space are proposed to evaluate the effect of the telescopic forearm on the dynamic load of the robot. Monte Carlo method is used to solve these two indices. This work is essential for the motion planning and control of the seven degrees of freedom spray-painting robot with a telescopic forearm.

Oscillation-free point-to-point motions of planar differentially flat under-actuated robots: a Laplace transform method

AbstractDifferentially flat under-actuated robots are characterized by more degrees of freedom (DOF) than actuators: this makes possible the design of lightweight cheap robots with high dexterity. The main issue of such robots is the control of the passive joint, which requires accurate dynamic modeling of the robot.Friction is usually discarded to simplify the models, especially in the case of low-speed trajectories. However, this simplification leads to oscillations of the end-effector about the final position, which are incompatible with fast and accurate motions.This paper focuses on planar $n$ -DOF serial robotic arms with $n-1$ actuated rotational joints plus one final passive rotational joint with stiffness and friction properties. These robots, if properly balanced, are differentially flat. When the non-actuated joint can be considered frictionless, differentially flat robots can be controlled in open loop, calculating the motor torques demanded by point-to-point motions. This paper extends the open-loop control to robots with a passive joint with viscous friction adopting a Laplace transform method. This method can be adopted by exploiting the particular structure of the equations of motion of differentially flat under-actuated robots in which the last equations are linear. Analytical expressions of the motor torques are obtained. The work is enriched by an experimental validation of a $2$ -DOF under-actuated robot and by numerical simulations of the $2$ - and $4$ -DOF robots showing the suppression of unwanted oscillations.

Readjustment of a robot for educational purposes

AbstractDevelopment of control of a five degrees of freedom robot is discussed in this paper. Only two robots were made, and one of these is in the University of Miskolc. The robot was made in the 80s for educational purposes, the electronic components were obsolete and control software was missing, therefore it became necessary to perform hardware improvements, and develop a new control program. Inverse kinematics problem of the robot is solved by geometric approach to formulate the joint angles, which will form the basis of the control. A braking system containing electromagnets for the robot is constructed to balance it. A printed circuit board is designed to establish the control of the system, the central element is a Cypress PSoC 5LP platform. The development of the control program is performed in software PSoC Creator 4.4. The developed control system of the robot can receive instructions from a computer via a designed special purpose user program, which is written in Python programming language. Thanks to the improvements, the robot has become operational. Thus, the robot can serve educational purposes performing different manipulation tasks. By completing the developments, students can get to know the structure and programming of the robot, its inverse kinematics problem. This will require the development of practice-oriented tasks in the future.

Projecting robot dynamics onto trajectories

AbstractMachines and mechanisms realize processes, from the shaping process of a milling machine and the motion process of an automotive system to the trajectory realization of a robot. The dynamics of a machine generated by a properly chosen set of constraints in combination with an appropriate drive system is designed to meet the prescribed requirements of the process, which is done by projecting the machine equations of motion on the process dynamics. We get a set of nonlinear relations, which represent the machine motion in terms of the required process motion. A well-known example is the projection of arbitrary many robot degrees of freedom (DOFs) on a given path resulting in a set of nonlinear equations with one DOF only, the path coordinate s. Application of this idea can be used to construct a mobility space $(\ddot{s}, \dot{s}, s)$ for any combination of coordinates and constraints. The paper presents a corresponding approach for n-link robots by applying multibody system theory. Method might be interesting for layout of machines and mechanisms. Practical aspects are discussed, and an example is given.

THE BIOMECHANICAL ANALYSIS OF A NOVEL IMPLANT FOR SCAPHOLUNATE INTEROSSEOUS LIGAMENT RUPTURE REPAIR

There is currently no commercially available and clinically successful treatment for scapholunate interosseous ligament rupture, the latter leading to the development of hand-wrist osteoarthritis. We have created a novel biodegradable implant which fixed the dissociated scaphoid and lunate bones and encourages regeneration of the ruptured native ligament. To determine if scaphoid and lunate kinematics in cadaveric specimens were maintained during robotic manipulation, when comparing the native wrist with intact ligament and when the implant was installed.Ten cadaveric experiments were performed with identical conditions, except for implant geometry that was personalised to the anatomy of each cadaveric specimen. Each cadaveric arm was mounted upright in a six degrees of freedom robot using k-wires drilled through the radius, ulna, and metacarpals. Infrared markers were attached to scaphoid, lunate, radius, and 3rd metacarpal. Cadaveric specimens were robotically manipulated through flexion-extension and ulnar-radial deviation by ±40° and ±30°, respectively.The cadaveric scaphoid and lunate kinematics were examined with 1) intact native ligament, 2) severed ligament, 3) and installed implant.Digital wrist models were generated from computed tomography scans and included implant geometry, orientation, and location. Motion data were filtered and aligned relative to neutral wrist in the digital models of each specimen using anatomical landmarks. Implant insertion points in the scaphoid and lunate over time were then calculated using digital models, marker data, and inverse kinematics. Root mean squared distance was compared between severed and implant configurations, relative to intact.Preliminary data from five cadaveric specimens indicate that the implant reduced distance between scaphoid and lunate compared to severed configuration for all but three trials.Preliminary results indicate our novel implant reduced scapho-lunate gap caused by ligament transection. Future analysis will reveal if the implant can achieve wrist kinematics similar to the native intact wrist.

Boomerang Algorithm based on Swarm Optimization for Inverse Kinematics of 6 DOF Open Chain Manipulators

In this study, a feasible swarm intelligence algorithm is proposed that computes the inverse kinematics solution of 6 degree of freedom (DOF) industrial robot arms, which are frequently used in industrial and medical applications. The proposed algorithm is named as Boomerang algorithm due to its recursive structure. The proposed algorithm aims to reduce the computation time to feasible levels without increasing the position and orientation errors. In order to reduce the computational time in swarm optimization algorithms and increase feasibility, an alternative definition method was used instead of the DH method in defining the robot arm kinematic configuration. The effect of the proposed alternative definition method in reducing the computational time is presented through example inverse kinematic analysis. The proposed algorithm was compared with 3 different particle swarm optimization (PSO) variants that include orientation in the inverse kinematic solution of 6 DOF robot arms. Comparative simulation studies were carried out with 20 randomly selected position and orientation data from the workspaces of PUMA 560 and ABB IRB120 manipulators to measure performance of the algorithms. Using the error and computation time values obtained from the simulation results, the algorithms are compared using the Wilcoxon nonparametric statistical test. When the simulation results are analysed by considering the calculation time, positioning accuracy and solution finding rates, it is seen that the Boomerang algorithm is more feasible than the other PSO variants. Verification of the simulation results, and the physical applications were carried out with the ABB IRB120 6 DOF robot arm. Simulation studies and experimental studies showed that the proposed algorithm may be an efficient method for inverse kinematics of time-critical applications.

Automatic Calibration of Tool Center Point for Six Degree of Freedom Robot

The traditional tool center point (TCP) calibration method requires the operator to use their experience to set the actual position of the tool center point. To address this lengthy workflow and low accuracy, while improving accuracy and efficiency for time-saving and non-contact calibration, this paper proposes an enhanced automatic TCP calibration method based on a laser displacement sensor and implemented on a cooperative robot with six degrees of freedom. During the calibration process, the robot arm will move a certain distance along the X and Y axes and collect the information when the tool passes through the laser during the process to calculate the runout of the tool, and then continue to move a certain distance along the X and Y axes for the second height calibration. After the runout angle is calculated and calibrated by triangulation, the runout calibration is completed and the third X and Y axis displacement is performed to find out the exact position of the tool on the X and Y axes. Finally, the tool is moved to a position higher than the laser, and the laser is triggered by moving downward to obtain information to complete the whole experimental process and receive the calibrated tool center position. The whole calibration method is, firstly, verified in the virtual simulation environment and then implemented on the actual cooperative robot. The results of the proposed TCP calibration method for the case of using a pin tool can achieve a positioning deviation of 0.074 and 0.125 mm for the robot moving speeds of 20 and 40 mm/s, respectively. The orientation deviation in the x-axis are 0.089 and −0.184 degrees for the robot moving speeds of 20 and 40 mm/s, respectively. The positioning repeatability of ±0.083 mm for the moving speed of 20 mm/s is lower than ±0.101 mm for the speed of 40 mm/s. It shows that lower moving speed can obtain higher accuracy and better repeatability. This result meets the requirements of TCP calibration but also achieves the purpose of being simple, economical, and time-saving, and it takes only 60 s to complete the whole calibration process.

Ideal Length and Diameter for Intramedullary Screw Fixation of Metacarpal Fractures: A Biomechanical Study

This biomechanical study evaluated the effect of intramedullary screw diameter and length relative to 3-point bending force and torsional force when used to stabilize metacarpal shaft fractures. Transverse osteotomies were made in the proximal metacarpal shaft in 36 middle finger metacarpal fourth-generation composite Sawbones. To compare screw diameters, antegrade intramedullary screws of 30-mm length were placed in 6 metacarpals, which included 4.7-mm Acutrak 2, Standard Acutrak 2 (4.0 mm), and Mini-Acutrak 2 (3.5 mm) screws. To compare screw lengths, metacarpals were fixated with Standard Acutrak 2 screws of 26, 30, or 34 mm in length, with screw tips bypassing the osteotomy by 6, 10, or 14 mm, respectively. A 6 degrees of freedom robot was used for torsional and 3-point bending testing. Increasing screw diameter demonstrated significant differences in both 3-point bending and torsional strengths. Maximum torsional loads were 69 Ncm (4.7-mm Acutrak 2), 45 Ncm (Standard Acutrak 2), and 27 Ncm (Mini-Acutrak 2) (P < .05). Loads to failure in the 3-point bending tests were 916 N (4.7-mm Acutrak 2), 713 N (Standard Acutrak 2), and 284 N (Mini-Acutrak 2) (P < .05). Differing screw lengths demonstrated significant differences with maximum torsional loads when comparing the 26-mm screws (22 Ncm) with 30- and 34-mm screws (45 and 55 Ncm, respectively) (P < .05). The 3-point dorsal bending strengths were significantly different between the 26-mm screws (320 N) and 30- and 34-mm screws (713 N and 702 N, respectively) (P < .05). The results demonstrated significantly higher torsional strength and resistance to 3-point bending with larger intramedullary screw diameters. Further, when selecting the intramedullary screw length, the screw tip should pass at least 10 mm beyond the fracture. This study provided biomechanical evidence to guide surgeons in selecting intramedullary screw diameter and length for treating metacarpal fractures.

Kinematic analysis and development of cable-driven rehabilitation robot for cerebral palsy patients

This study aimed to analyze the kinematic development of a rehabilitation cable robot for patients with cerebral palsy problems. For this purpose, the walking pattern of a healthy person was analyzed in the robot by extracting his kinematic model. Therefore, a seven-link model was considered, and changes in the mass center of the links and then movements during the gait cycle were obtained with the angles related to joint changes. Next, the person’s integration with the rehabilitation cable robot was investigated with the resolution of the direct kinematic problem. In addition, the change-related outputs of the cables were obtained by the person’s movement and the attached belt. The robot was further proposed because the specific change diagram of the cables facilitates understanding how much motor torque is needed to change the length of the cable. It is noteworthy that the static person balance is provided in the existing rehabilitation robots. However, in this structure, the balance is done by the six degrees of freedom robot so that the robot can return the person to the original path when he loses his balance. Cable systems for the lower limbs (thighs and shanks) are also simulated to rehabilitate the patient. The obtained results from the simulation and the obtained output from kinematic equations for lower limb movements were also compared, and the highest deference was 2.2, 1.8, 1.8, and 1.5% for shank-back, shank-front, thigh-back, and thigh-front of the leg in the corresponding points in the outputs of both software, respectively.

Decentralized adaptive control applied to two links of a five degrees of freedom robot, using the polynomial technique

The objective of this work is to design and implement decentralized adaptive controllers in order to perform the position control of two links of an electromechanical manipulator robot with five degrees of freedom (DOF 5). The manipulator robot is consisted of five rotational joints, four links and a claw. Five DC motors are used to drive the robot and the motion transmission from the motors to the joints is achieved by gear trains. Models of the manipulators robots are obtained using Newton-Euler or Lagrange equations; and are coupled and nonlinear. In this work, the model of the links of the manipulator robot is obtained in real time for each sampling period. The parameters of the links to be controlled are identified by recursive least squares (RLS) method, according to data from the links, and are used in the designs of adaptive controllers for the positions control of the joints of the links under analysis. In the end, the experimental results are presented, like the evaluation of the performance achieved by the manipulator robot links.

Active Disturbance Rejection Control for Robot Manipulator

Active Disturbance Rejection Control (ADRC) is a control methodology used in chemical processes, aircraft, motors, and other systems. This paper compares the results of an ADRC controller to a Proportional Integral Derivative controller (PID), applied to two degrees of freedom robots. A Linear Extended State Observer (LESO) is used to reconstruct the state variables and unknown parameters needed to control the position of each link. The ADRC can achieve the tracking position and estimate the velocity of each link. The results of the simulation program are shown.

An Automatic, Contactless, High-Precision, High-Speed Measurement System to Provide In-Line, As-Molded Three-Dimensional Measurements of a Curved-Shape Injection-Molded Part

In the manufacturing of injection-molded plastic parts, it is essential to perform a non-destructive (and, in some applications, contactless) three-dimensional measurement and surface inspection of the injection-molded part to monitor the part quality. The measurement method depends strongly on the shape and the optical properties of the part. In this study, a high-precision (±5 µm) and high-speed system (total of 24 s for a complete part dimensional measurement) was developed to measure the dimensions of a piano-black injection-molded part. This measurement should be done in real time and close to the part’s production time to evaluate the quality of the produced parts for future online, closed-loop, and predictive quality control. Therefore, a novel contactless, three-dimensional measurement system using a multicolor confocal sensor was designed and manufactured, taking into account the nominal curved shape and the glossy black surface properties of the part. This system includes one linear and one cylindrical moving axis, as well as one confocal optical sensor for radial R-direction measurements. A 6 DOF (degrees of freedom) robot handles the part between the injection molding machine and the measurement system. An IPC coordinates the communications and system movements over the OPC UA communication network protocol. For validation, several repeatability tests were performed at various speeds and directions. The results were compared using signal similarity methods, such as MSE, SSID, and RMS difference. The repeatability of the system in all directions was found to be in the range of ±5 µm for the desired speed range (less than 60 mm/s–60 degrees/s). However, the error increases up to ±10 µm due to the fixture and the suction force effect.

ABB Robotic Laser Doppler Anemometry Measurements With RobotStudio® With An Open Wind Channel And An Ellipsoid

Laser Doppler anemometry is a state-of-the-art non-invasive experimental flow measurement technique. Traditionally used linear traversing units can only change the position of the measurement probe, but cannot change the orientation of the probe. A six degrees of freedom robot can simplify and fasten up the pose planning and measurement process real-offline. A developed LDA software plug-in for RobotStudio is used to real-offline plan and perform flow measurements in an open wind channel (flow rate = 300 m³/h) with an ellipsoid (diameter y=z = 140 mm and x = 40 mm). In 25 mm, 20 mm, 15 mm, 10 mm, 5 mm and 2 mm orthogonal distance of the ellipsoid surface the tangential velocity component is determined. Accuracy and repeatability of the robot-LDA system is found and compared to the traditional linear traversing system. Results show a positive velocity gradient towards the axis of the wind channel with a velocity range of 4.4 – 20.3 m/s. At 25 mm distance the tangential velocity is in the range of 4.4 – 12.5 m/s, at 20 mm 7.6 – 17.5 m/s, at 15 mm 12.1 – 19.7 m/s, at 10 mm 16.5 – 20.1 m/s, at 5 mm 19.0 – 20.2 m/s and at 2 mm 18.3 – 20.3 m/s. In positive y and negative z-direction, a reduction of the tangential velocity component is found in all measurements. At a distance of 25 mm, the measurement surface is slightly outside to the wind channel inlet (diameter = 80 mm). The closer the measurement surface is at the wind channel axis, the higher is the wind channel axial component. Robot-LDA average accuracy of 13 µm and repeatability of 10 µm is in the range of the linear traversing unit where the accuracy is 20 µm and the repeatability is 6 µm. The robot-LDA measurement system is an alternative to the existing linear-LDA with the advantages of real-offline robot path planning for arbitrary surfaces requiring six degrees of freedom probe placement.

A Novel Framework for Mixed Reality–Based Control of Collaborative Robot: Development Study

Background Applications of robotics in daily life are becoming essential by creating new possibilities in different fields, especially in the collaborative environment. The potentials of collaborative robots are tremendous as they can work in the same workspace as humans. A framework employing a top-notch technology for collaborative robots will surely be worthwhile for further research. Objective This study aims to present the development of a novel framework for the collaborative robot using mixed reality. Methods The framework uses Unity and Unity Hub as a cross-platform gaming engine and project management tool to design the mixed reality interface and digital twin. It also uses the Windows Mixed Reality platform to show digital materials on holographic display and the Azure mixed reality services to capture and expose digital information. Eventually, it uses a holographic device (HoloLens 2) to execute the mixed reality–based collaborative system. Results A thorough experiment was conducted to validate the novel framework for mixed reality–based control of a collaborative robot. This framework was successfully applied to implement a collaborative system using a 5–degree of freedom robot (xArm-5) in a mixed reality environment. The framework was stable and worked smoothly throughout the collaborative session. Due to the distributed nature of cloud applications, there is a negligible latency between giving a command and the execution of the physical collaborative robot. Conclusions Opportunities for collaborative robots in telerehabilitation and teleoperation are vital as in any other field. The proposed framework was successfully applied in a collaborative session, and it can also be applied in other similar potential applications for robust and more promising performance.

ABB IRB 120-30.6 Build Procedure in RoboDK

Purpose: Research on robotics needs a robot to experiment on it. The actual industrial robot is costly. So, the only resort is to use a Robot simulator. The RoboDK is one of the best robot simulators now. It has covered most of the popular industrial robots. Its interface is straightforward. Just open the software, download the robot as we need, and start experiments. Up to that, no issue was found anywhere. However, the problem begins when we want to build the simulated robot by own. Lots of complexity arises like coordinate assignment, rotation not aligned, length mismatch, robot not synced with DH parameter. We begin to find some documents for making the robots. A few bits of the document are present. That is why we research it. After doing that, we prepared this paper for the researcher who wants to develop the simulated robot independently. This paper can be referenced for them. To minimize the complexity of our research, we study an industrial robot, ABB IRB 120-30.6. It is a good and popular robot. It is six degrees of freedom robot. We will use the specification and STEP file from their respective website and build a simulated robot from the STEP file for our research purpose. Design/Methodology/Approach: We will create a simulated robot from ABB IRB 120-30.6 STEP file. To create a robot by own, we took the help of the IRB 120 robot model. To demonstrate as simple as possible, we start with that robot whose default design is already present. We match and tune the joint coordinate based on robot parameters through this experiment. Findings/results: Here, we see how to create a custom robot. Using the IRB 120 robot model, we will create a robot model step by step. Furthermore, it will move it around its axis. Originality/Value: Using this experiment, the new researcher can get valuable information to create their custom robot. Paper Type: Simulation-based Research.

Experimental and Numerical Simulation of Neuro Fuzzy Based Cartesian Robot for Soft Material Cutting

Present technology used for soft material cutting robot are laser, water-jet, ultrasonic, plasma and oxy-gas cutting. The scope for designing and fabrication of soft material cutting robots are increasing due to its cost effectiveness and quality of cutting. Cartesian robots are mainly used in assembly and manufacturing applications. They also have a high degree of mechanical rigidity, accuracy, and repeatability. A previous work of more elementary kind was used as a skeleton model to start this work The purpose of the work is the maintenance and implementation of a 4 Degree of freedom robot and also to provide intelligence to the robot using Fuzzy logic and Neuro-Fuzzy for soft material cutting. The kinematic modeling of robot manipulator is done using Denavit-Hartenberg (D-H) parameterization method and Euler-Lagrange method is used for dynamic analysis to determine actuator torque for each joint. The image is acquired with the help of the digital camera which is fixed in a suitable position so that it can scan the entire workspace. Prewitt edge detection algorithm was used for image processing and analysis. The signal for the cutting is interfaced through the Arduino Uno r3 controller.

A Study on the Response of the Rehabilitation Lower Device using Sliding Mode Controller

This paper presents the application of the sliding mode controller to simulate the control of a 3 Degree of Freedom (DoF) robot model that supports lower extremity rehabilitation exercises for stroke patients. The 3 DoF robot model has an established dynamic differential equation for each joint. This paper studied the response of links of the research model with a sliding mode controller proposed as the control solution. Matlab software was used in simulations of ankle, knee, and hip joints' drive for 2 cases, without and with load. Compared with other studies, the research results show that the sliding controller results in slight angular errors when applied to the research model, while the torque of the joints remains low. This result is the basis for calculating and selecting parameters for the actuator when manufacturing the actual equipment.

Evaluation of the Intact Anterior Talofibular and Calcaneofibular Ligaments, Injuries, and Repairs With and Without Augmentation: A Biomechanical Robotic Study

Background: Acute ankle sprains are common injuries. The anterior talofibular (ATFL) and calcaneofibular ligaments (CFL) are the most injured lateral structures. However, controversy exists on the optimal surgical treatment when the injury is both acute and severe or becomes chronic and unstable. Studies have evaluated the biomechanics of these ligaments, but no studies have robotically evaluated injury effects and surgical treatment of ATFL or ATFL and CFL injuries. Purpose: To quantitatively evaluate biomechanical effects of ATFL and CFL lesions, ATFL repair, ATFL and CFL repair, and augmentation of ATFL on ankle stability. Study Design: Controlled laboratory study. Methods: Ten nonpaired cadaveric ankles were tested using a 6 degrees of freedom robot. Each ankle underwent testing in the following states sequentially: (1) intact, (2) ATFL cut, (3) CFL cut, (4) ATFL repair + CFL cut, (5) ATFL repair + CFL repair, and (6) ATFL repair with augmentation with suture tape + CFL repair. Testing included 88 N anterior drawer and 5 N·m varus talar tilt tests at 0° and 30° of plantarflexion, and 88 N Cotton test at 0° of plantarflexion. Results: After all surgical treatments ankles still had increased laxity compared with intact state testing, except after augmented ATFL repair + CFL repair in anterior drawer testing at 30° of plantarflexion (P = .393). Sectioning the CFL caused a significant increase in talar tilt compared with the ATFL cut state at 0° (P < .001) and 30° of plantarflexion (P < .001), but no increase in anterior drawer or Cotton tests. Conclusion: Complete native stability may not be attainable at time zero repair with the tested treatments. The option that best returned stability in anterior translation was augmented ATFL repair with nonaugmented CFL repair. The importance of the CFL as a primary ligamentous stabilizer for talar tilt was confirmed. Clinical Relevance: Evaluating lateral ankle stability and treatment with a 6 degrees of freedom robot should help delineate optimal treatment options. Findings in this study show that none of the repair methods at time zero restored kinematics to the intact state. Of the tested states, the augmented ATFL repair with CFL repair was the best option for controlling anterior translation at time zero. The importance of addressing the CFL to correct talar tilt instability was suggested as was the importance of a period of immobilization before beginning protected rehabilitation. The benefit of ATFL repair augmentation with suture tape is in limiting the postoperative motion in an anterior drawer motion to just 0.5 to 1 mm, but there was no significant improvement to talar tilt even with CFL repair, suggesting that further consideration should be given to CFL augmentation in future studies.

Two-Stage Water Jet Landing Point Prediction Model for Intelligent Water Shooting Robot

In this paper, an intelligent water shooting robot system for situations of carrier shake and target movement is designed, which uses a 2 DOF (degree of freedom) robot as an actuator, a photoelectric camera to detect and track the desired target, and a gyroscope to keep the robot’s body stable when it is mounted on the motion carriers. Particularly, for the accurate shooting of the designed system, an online tuning model of the water jet landing point based on the back-propagation algorithm was proposed. The model has two stages. In the first stage, the polyfit function of Matlab is used to fit a model that satisfies the law of jet motion in ideal conditions without interference. In the second stage, the model uses the back-propagation algorithm to update the parameters online according to the visual feedback of the landing point position. The model established by this method can dynamically eliminate the interference of external factors and realize precise on-target shooting. The simulation results show that the model can dynamically adjust the parameters according to the state relationship between the landing point and the desired target, which keeps the predicted pitch angle error within 0.1°. In the test on the actual platform, when the landing point is 0.5 m away from the position of the desired target, the model only needs 0.3 s to adjust the water jet to hit the target. Compared to the state-of-the-art method, GA-BP (genetic algorithm-back-propagation), the proposed method’s predicted pitch angle error is within 0.1 degree with 1/4 model parameters, while costing 1/7 forward propagation time and 1/200 back-propagation calculation time.

Plug-and-Train Robot (PLUTO) for Hand Rehabilitation: Design and Preliminary Evaluation

Hand neurorehabilitation involves training movements at the forearm, wrist, fingers, and thumb joints. Assisted training of all these joints requires either one complex multiple degree-of-freedom (DOF) robot or a set of simple robots with one or two DOF. Neither of these is economic or clinically viable. This paper addresses this problem with the PLUg and train rObot (PLUTO)- a single DOF robot that can train multiple joints one at a time. PLUTO has a single actuator with a set of passive attachments/mechanisms that can be easily attached/detached to train for wrist flexion-extension, wrist ulnar-radial deviation, forearm pronation-supination, and gross hand opening-closing. The robot can provide training in active and assisted regimes. PLUTO is linked to performance adaptive computer games to provide feedback to the patients and motivate them during training. As the first step towards clinical validation, the device usability was evaluated by 45 potential stakeholders/end-users of the device, including 15 patients, 15 caregivers, and 15 clinicians with standardized questionnaires: System Usability Scale (SUS) and User Experience Questionnaire (UEQ). Patients and caregivers were administered the questionnaire after a two-session training with the robot. Clinicians, on the other hand, had a single session demo, after which feedback was obtained. The total SUS score obtained from patients, clinicians, and caregivers was 73.3 ± 14.6 (n = 45), indicating good usability. The UEQ score was rated positively in all subscales by both patients and clinicians, indicating that the features of PLUTO match their expectations. The positive response from the preliminary testing and the feedback from the stakeholders indicate that with additional passive mechanisms, assessment features, and optimized ergonomics, PLUTO will be a versatile, affordable, and useful system for hand rehabilitation.